Combustion within an internal combustion engine is a time sensitive process in which the opening and closing of valves, fuel injection, and spark ignition must occur at precise times in relation to the stroke of the associated cylinder in order to meet emission, performance and efficiency objectives. Measuring crankshaft position is a known method to approximate cylinder positions. One method to measure crankshaft position is to link a target wheel to the crankshaft and sense the target wheel rotation. This target wheel includes features which allow individual revolutions of the wheel and fractions thereof to be sensed.
As already mentioned, timing is very important to the combustion process. Small manufacturing variations and dynamic system conditions may introduce errors crankshaft position measurements via a target wheel. These errors may compromise the combustion process, so it is therefore advantageous to quantify these errors and adapt to them. While a portion of these errors are driven by manufacturing variations that can be measured while the engine is stationary, the effects of the dynamic system forces interact with these manufacturing variations and may not be discounted. In addition, the system experiences additional deformations while in an acceleration mode, a deceleration mode, or while being driven by the combustion process.